Projectors are well known for displaying images on various display surfaces, such as projection screens, walls, sheets, and so forth. Typically, projectors receive their power from alternating current (AC) power supplied to the building in which they operate. More recently, projectors have been shrinking in size and are now operable from portable power sources, such as rechargeable batteries. As the sizes of projectors decrease, the variety of their uses increases. For example, miniature projectors or microprojectors can be used either as a mobile desktop projector or as a handheld device. Additionally, small projectors may be integrated into or connectable to mobile wireless telephones, personal digital assistants (PDAs), MP3 players, notebook computers, or other portable electronic devices. For instance, a microprojector may be connectable to the USB port of a laptop computer so as to receive power from the computer's power source (e.g., battery).
As cell phones and other portable electronic devices have become smaller for improved portability, efficient use of the device's battery has become very important to maximize the time between recharging. Consequently, the portability of electronic devices can be improved through power management. While various portable electronic devices, such as cell phones and laptop computers, implement power management policies to extend battery life by deactivating certain features after a fixed, predetermined period of time (e.g., dimming a cell phone's display backlight alter a preset time period) or after a predetermined lime period of inactivity (e.g., activating a screen saver on a notebook computer after detecting a lack of user interface activity), no power management policy has been established for facilitating use of a projector in or with portable electronic devices.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated alone or relative to other elements to help improve the understanding of the various embodiments of the present invention.